This invention relates to a process for the manufacture of twistless or substantially twistless yarn and the yarn obtained according to this process. For this purpose, a sliver of staple fiber is drafted to form a thinner fiber strand, the fiber strand is false twisted and bonded with the aid of a bonding agent which can be removed from products manufactured using the twistless yarn.
A prior process is known from U.S. Pat. No. 3,447,310. In that process the sliver is, before, during or after drafting, but before false twisting, washed in an unsaturated wet state with an excess of starch granules in suspension. After false twisting, the fiber strand is subjected to heat treatment which activates that bonding agent and thereafter the fiber strand is dried.
Slivers composed of predominately hydrophilic fibers absorb sufficient quantitites of the bonding agent yielding a yarn of sufficient and uniform strength. Thus, for example, cotton fibers can be processed according to that known method, only after bleaching, scouring and/or soaking for several days in water.
It is an object of the present invention to provide an improved bonding process for both hydrophobic and hydrophilic fibers in fiber strands. For this purpose, a water-soluble cation-active polymer promotes fiber bonding. Consequently, cotton fibers no longer require prolonged pre-draft bleaching, scouring or soaking thereby decreasing process time. The cation-active bonding agent also decreases the soiling of process machinery.
Accordingly, the present invention provides a method for manufacturing hydrophobic or hydrophilic slivers into twistless or substantially twistless yarn using a removable water-soluble cation-active polymer bonding agent. Cation-active carbohydrates, such as quaternized starches with substitution degrees at between about 0.005 and 0.500 are suitable water soluble cation-active polymer bonding agents for use herein.